Polyvinyl butyral is widely used in combination with one or more layers of glass or other glazing material to provide a laminate which is resistant to shattering. In recent years, effort has been directed to the preparation of other composites which can be used in combination with glass to provide not only resistance to shattering but protection against abrasion and scratching when used as a component of a glazing material.
The preparation of laminates for use in automotive windshields presents unusually stringent requirements. In addition to the basic requirements noted above, an automotive windshield must provide high impact resistance and excellent optical clarity. Beyond this, for improved fuel efficiency, these characteristics should desirably be provided at a minimum weight. Previously, attempts to provide this combination of properties have often resulted in a laminate that performed well at ambient conditions, but crazed when exposed to especially high or low temperatures or humidity.